Method of making a ball-bearing retainer



Dec. 30, 1969 J. L. VANNEST METHOD OF MAKING A BALL-BEARING RETAINER 2Sheets-Sheet 1 Original Filed'April 8, 1966 nwsn'ron JAMES L. VANNEST BYATTORNE s METHOD OF MAKING A BALL-BEARING RETAINER Original Filed April8, 1966 Dec. 30, 1969 J. L. VANNEST 2 Sheets-Sheet 2 INVENTOR JAMES L.vmmzs'r BY ATTORNE s United States Patent 3,486,212 METHOD OF MAKING ABALL-BEARING RETAINER James L. Vannest, New Britain, Conn., assignor, bymesne assignments, to Textron Inc., Providence, R.l., a corporation ofDelaware Original application Apr. 8, 1966, Ser. No. 541,243, now PatentNo. 3,399,936, dated Sept. 3, 1968. Divided and this application Mar.18, 1968, Ser. No. 739,572 Int. Cl. B21d 53/12; B21h 1/12 US. Cl.29148.4 Claims ABSTRACT OF THE DISCLOSURE The invention contemplatesmanufacture of a ball-retainer ring for a ball bearing, by initiallyproviding radial holes in an annular ring blank, having inward andoutward projections extending radially of the body of the ring blank, ator between adjacent holes. The holes are of less than ball diameter. Theholes are then enlarged to a diameter larger than ball diameter, and toan inward extent short of the radially inner limit of the inwardprojections to form ball-retaining seats on the inward projections; theholes are also enlarged to a diameter larger than ball diameter, in theradially outward direction, to an extent short of the radially outerlimit of the outward projections to form ball-retaining seats on theoutward projections. Balls which slightly interfere with hole en trancesare then assembled by snap action, against slight resilient deflectionof the projections, into unit-handling relation with the retainer ring.

This is a division of application, Ser. No. 541,243, filed Apr. 8, 1966,now Patent No. 3,399,936, dated Sept. 3, 1968.

This invention relates to a retainer for a ball bearing and to a methodfor making the same.

In the manufacture of conventional retainer rings of the type referredto herein, means in the form of ball retaining nibs or fingers areprovided on the outer surface of the retainer to maintain the balls intheir respective pockets in the retainer. These nibs are formed bymachining the retainer in such a manner that the balls may be insertedin their pockets in a radially inward direction past the nibs. The ballsare then restrained from falling out of their pockets by bending atleast a portion of each outer nib into a position of interference intothe path of entry of the balls.

The retainer thus made has several important disadvantages. One of theseis that considerable difficulty is encountered in producing just theright amount of bending of each nib so that the associated ball issuificiently restrained from falling out of its pocket; at the sametime, the bending must not be so great that insuflicient ball freedom inthe radial direction results or that cracking of the nib and failurethereof are likely to result during operation. As a matter of actualexperience, it has been found that the amount of bending of the nibsrequired to retain the balls in their pockets not infrequently causescracking of the nib and failure of the bearing during operation. Afurther disadvantage is that uniformity in the amount of bending of thenibs from pocket to pocket is extremely difficult to achieve.

Accordingly, an object of the invention is to provide a method formaking a bearing retainer having the desirable features of greaterreliability, longer life and a lower failure rate.

Yet another object is to provide a method for making a bearing retainerhaving a more uniform degree of radial ball freedom among the variousballs in a given retainer.

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A further object is to achieve the foregoing objects with a method whichinherently assures symmetry of ball-retaining contour formations bothbefore and after assembly into unit-handling relation with a complementof balls.

All of the objects, features and advantages of this invention and themanner of attaining them will become more apparent and the inventionitself will be best understood by reference to the following descriptionof an embodiment of the invention taken in conjunction with theaccompanying drawing, in which:

FIG. 1 is a diametral sectional view through a ball bearing, showing oneform of retainer according to the invention,

FIG. 2 is a fragmentary development of a section of a retainer accordingto a first embodiment of the invention, as viewed from the outside ofthe retainer,

FIG. 3 is a generally axially viewed fragment of the retainer shown inFIG. 2, before machining to its finished form,

FIG. 4 is a view similar to FIG. 3 but illustrating the retainer in itsfinished form,

FIG. 5 is a fragmentary development of a section of the retainer of FIG.2 as viewed from the inside of the retainer,

FIG. 6 shows a transverse section of the retainer taken on the line 66of FIG. 4,

FIG. 7 is a fragmentary development of a section of a retainer accordingto a second embodiment of the invention, as viewed from the outside ofthe retainer,

FIG. 7A is a view, greatly enlarged, of a section of the retainer ofFIG. 7, showing details of means for restrain ing the balls from fallingradially outwardly out of the retainer,

FIG. 8 is a generally axially viewed fragment of the retainer shown inFIG. 7, before machining to its finished form,

FIG. 9 is a view similar to FIG. 8 but illustrating the retainer in itsfinished form,

FIG. 10 is a fragmentary development of a section of the retainer ofFIG. 7 as viewed from the inside of the retainer,

FIG. 11 is a view taken along the line 1111 of FIG. 10,

FIG. 12 shows a transverse section of the retainer of FIG. 7 taken onthe line 1212 of FIG. 9.

FIG. 13 shows a transverse section of the retainer of FIG. 7 taken onthe line 1212 of FIG. 9,

FIGS. 14A, 14B and 14C show transverse sectional views illustratingditferent steps during the manufacture of a retainer according to athird embodiment of the invention, these views being taken at a ballcenter point on the retainer, such as at 6-6 as seen in FIG. 4.

.Briefiy stated, there is provided in accordance with the invention, animproved retainer and a method for making the same wherein an annularring is provided having a plurality of circumferentially spaced holes orpockets for reception of the halls. Between the pockets and extendinggenerally radially inwardly are fingers provided with suitable seats forretaining the balls in the pockets. These fingers are formed of suchmaterial and dimensions as to be sufliciently resilient to permitsidewise elastic deformation thereof to allow the balls to be insertedinto the pockets by urging the same in a radially outward direction.Upon the application of sufficient force the balls spread the fingerssufliciently to allow the balls to pop into the pockets. The balls arethen restrained, in unit-handling relation with the ring, againstfalling out of the pockets in an inwardly radial direction by return ofthe fingers to their unstressed or normal positions.

The halls are restrained from falling radially outward out of theretainer by restraining means which preferably form line contact withthe surface of the ball in each pocket. Such ball outer restrainingmeans may take various forms.

The retainer in its rough or original form preferably includes ballpockets or radial holes which are slightly smaller than the diameter ofthe balls to be received therein; the ring, thus apertured, has aninwardly extending projection and an outwardly extending projec tionadjacent each hole and of limited arcuate extent about the hole axes atthe location of adjacency to each end of each hole. These pockets arethen enlarged by means of a suitable pocket-enlarging tool. This toolmay also form generally spherical seats on the inwardly directed fingersbetween the pockets so that the balls therein may rest radially inwardlytherein. The ball outer restraining means are also preferably formed bymeans of the same tool which forms these generally spherical seats; suchtool may be, for example, the well known camactuated recessing tool, ormay be any other suitable machine arrangement. The outer restrainingmeans thus formed may also take the form of a seat. In one embodimentthis latter seat means may provide line contact between the retainer andthe balls generally in the central region intermediate the sides of theretainer ring; in another embodiment, such line contact may be providedgenerally toward the edges of the retainer ring by generally annularflanges adjacent the sides of the retainer.

The pockets thus formed in accordance with the invention are, generallyspeaking, formed cylindrically or circularly by the cam-actuatedrecessing tool so that the outer restraining means and also the inwardlydirected fingers so formed prevent movement of the ball out of thepocket either inwardly or outwardly, except upon the application ofconsiderable radial force on the balls.

Referring now to the drawing, FIG. 1 illustrates a complete ball bearingwhich embodies an inner ring and an outer ring 12 With a plurality ofballs 14 therebetween. The balls are held in a retainer 16 which maytake a variety of specific forms in accordance with differentembodiments of the invention. In the particular form shown in FIG. 1,the inner ring 10 comprises two halfsections held together in any mannerwell known to those skilled in the art.

FIGS. 2-6 show different views of the retainer 16 in accordance with afirst embodiment of the invention. The retainer 16 shown may be made ofa variety of suitable materials such as, for example, bronze or steel,is annular in shape, and is provided with circumferential equally spacedgenerally radial ball pockets 18. Between adjacent ball pockets 18 thereare provided radially inwardly directed fingers 20 and radiallyoutwardly extending lugs 22. The pockets 18 may be drilled, cast orforged, as seen in FIG. 3, to a size smaller than that of the diameterof the balls to be received therein, these pockets being enlarged bysuitable machining to proper size before insertion of the balls 14. Inthe preferred form, a suitable cam-guided recessing tool is run axiallyinto each pocket and forms a generally cylindrical shaped pocket to asize to properly receive the balls, as seen in FIG. 4, the machiningbeing continued inwardly so as to form generally spherical surfaces 24on the inner ends of the fingers 20. The two facing spherical surfaces24 on each pocket 18 form generally spherical seats for the balls toprevent them from dropping radially inwardly out of the retainer.

The lugs 22 at the radially outer side of the retainer 16 are preferablyformed also by the same cam-actuated recessing tool that is used to formthe spherical surfaces 24 on the fingers 20. Since this tool cuts acircular path, the lugs 22 present generally spherical surfaces 26 whichalso face one another.

In FIG. 4, one of the balls 14 is illustrated in various positions. Theposition indicated by the solid line 14A is that of the ball when theretainer and balls are mounted in the bearing of FIG. 1. The lowerposition indicated by the dashed lines 14B illustrates the position ofthe ball when held in its inner radial position by the sphericalsurfaces 24 on the fingers 20. The position of the ball indicated by theupper dashed lines 14C indicates the uppermost position of the ball,restrained in its outermost position in its pocket against radiallyoutward movement by the generally spherical surfaces 26 on the lugs 22.

The ball 14 is inserted into the pocket as seen in FIG. 4 by popping thesame in a radially outward direction past the spherical surfaces 24 onthe fingers 20. For this purpose, the fingers 20 are dimensioned so asto have a length/thickness ratio that will provide sufiicient elasticityto allow the ball to spread the fingers 20 laterally enough to cause theball to pass into its pocket without exceeding the elastic limit of thefingers. As soon as the ball has passed into the pocket, the fingers ofcourse return to their normal position to restrain the ball from fallingradially inwardly out of its pocket.

FIGS. 7l3 show different views of a retainer 30 in accordance with asecond embodiment of the invention. The retainer 30 includes a centralbody portion 32 which extends around the ring and comprises the mainring body portion. A plurality of equally spaced generally radial ballpockets 34 are provided in the central body portion 32 for receivingballs 36. Annular flanges 38 are provided at the edges of the retainer30 and are spaced from one another at a distance slightly less than thediameter of the balls 36 to be received in the pockets 32. These flanges38 extend radially outwardly from the main body portion 32 between theballs. Between adjacent ball pockets 34 there are provided radiallyinwardly directed fingers 40A. 40B, 40C and 40D, see especially FIGS. 9,10, 12 and 13. As will be best appreciated from these figures, fourfingers such as those 40A40D are associated with each ball pocket 34 andeach pair of adjacent fingers such as 40A 40B or 40C-40D are spaced fromone another by a gap 42 as shown in FIG. 1.2. :In the preferred form ofthe ring as originally cast the finger pairs 40A40B and 40C-40D eachcomprise one continuous inwardly extending metal portion 40 as seen inFIG. 8, with the gap 42 non-existent. These metal portions 40 are thensuitably machined to produce the gap 42, thus forming the finger pairs40A- 40B and 40C-40D (see FIGS. 9, 10 and 12). This embodiment may alsoutilize a single inwardly extending finger between adjacent pockets, aswill be understood.

As in the first embodiment of the invention described above, the pockets34 in this second embodiment may be drilled, cast or forged, as seen inFIG. 8 to a size smaller than that of the diameter of the balls to bereceived therein, these pockets also being enlarged by suitablemachining to proper size before insertion of the balls. Such machiningmay be accomplished using the camguided recessing tool referred toabove, to form the generally cylindrically shaped pockets 34 to theproper size to receive the balls 36. As the tool is moved axially intothe pocket 34, generally spherically shaped surfaces 44A, 44B, 44C and44D are formed on the inwardly extending fingers 40A, 40B, 40C and 40Drespectively. These spherically shaped surfaces 44A-44D form generallyspherical seats for the balls 36 to prevent the same from droppingradially inwardly out of the retainer 30.

The cam-actuated recessing tool is also used to form ball outer-limitrestraining means which in the present embodiment of FIGS. 7-13 take theform of arcuate projections 46, these projections extending generallyaxially to the retainer 30 and being most clearly seen in FIG. 7A andFIG. 12. These arcuate projections 46 are formed generally opposite oneanother on the opposing flanges 38, two such projections being providedfor each ball pocket 34. The projections 46 are spaced at a distancefrom one another whereby the maximum distance between any two opposingprojections is less than the diameter of the ball so that the same maybe restrained from falling radially outwardly out of the retainer.Further, these projections 46 are very narrow in height at their pointsof contact with the ball 36 and are preferably so narrow as to providesubstantial line contact with the ball they serve to restrain.

In FIG. 12, one of the balls 36 is illustrated in two differentpositions. The position indicated by the solid line 36A is that of theball within the ball-filled retainer mounted in its bearing assembly.The upper position indicated by the dashed lines 36B illustrates theposition of the ball when held in its outer radial position by thearcuate line-contact projections 46 on the flanges 38. In FIG. 11, thedashed lines 360 illustrate the ball 36 in its lowermost position whereit is restrained from falling radially inwardly out of the retainer byvirtue of the seat provided by the four generally arcuate surfaces44A-44D on the inwardly extending fingers 40A-40D.

The ball 36 is inserted into its pocket in a manner similar to thatdescribed above in connection with the first embodiment. Thus the ball36 is urged into its pocket 34 by applying radially outwardly directedforce against the ball to thereby spread the fingers 40A-40Dsufiiciently to allow the ball to pass into the pocket, after which thefingers return to their normal positions to restrain the ball fromfalling radially inwardly out of its pocket. The length/ thickness ratiomust of course be chosen, as above, for the particular retainer materialemployed and the dimensions between opposing fingers 40A-40D relative tothe ball diameter, so that the elastic limit of the fingers is notexceeded as the ball is popped into its pocket.

FIGS. 14A, 14B and 14C illustrate a third embodiment of the retainer ofthis invention and a method for making the same. The structure of thisthird embodiment includes the radially inwardly directed single fingers20 of the first embodiment and the outer flange 38 feature of the secondembodiment.

The third embodiment structure of FIGS. 14A, 14B and 14C is preferablymanufactured by a somewhat different method than employed above andincludes first forming an annular ring 50 as seen in FIG. 14A. This ring50 may be formed by any suitable method such as for example casting,forging, machining or the like. This ring 50 is next machined to form acentral annular recess 52, thereby producing the annular flanges 54adjacent thereto. Suitable machining operations are also carried out onthe inner surface 56 of the ring 50 to produce the inwardly extendingfingers 58 as seen in FIG. 14B. Ball pockets 60 similar to those alreadydescribed are then formed in the retainer ring body 50 between theinwardly extending fingers 58. Each ball pocket 50, see FIG. 14C, ispreferably formed by the cam-actuated recessing tool or other suitablemachine arrangement, which is caused to advance in a radially outwarddirection to an accurately predetermined point 62, thereby forming theflange projections 64 as seen in FIG. 14C. As with the construction ofthe second embodiment above, it will be clear that the balls will berestrained from falling radially outwardly out of the retainer of FIG.14C by the outer flange projections 64 and that the same will makegenerally line contact therewith.

It will be clear that during actual manufacture the order of the varioussteps just described may be varied. For example, the ball pockets 60 maybe formed prior to the formation of the inwardly extending fingers 58.Other modifications will occur to those skilled in the art.

In accordance with the invention described above, it will be appreciatedthat there is provided an improved retainer ring construction and also amethod for making the same whereby the advantage of greater reliability,longer life and lower failure rate during operation of the retainer areenjoyed. Additionally, the retainer thus made provides a more uniformdegree of radial ball freedom among the various balls in a givenretainer while maintaining the foregoing advantages.

While the foregoing description sets forth the principles of theinvention in connection with specific apparatus, it is to be understoodthat the description is made only by way of example and not as alimitation of the scope of the invention as set forth in the objectsthereof and in the accompanying claims.

What is claimed is: 1. A method for making an annular ball retainer ringcomprising the steps of forming a ring with a plurality of spaced radialholes with an inwardly extending finger between adjacent holes and withportions extending radially outwardly of the body of said ring, theholes having a diameter smaller than the diameter of the balls to bereceived therein, enlarging each of said holes with a cam-actuatedrecessing tool to a diameter larger than that of said balls and inwardlya predetermined distance short of the radially inner limit of saidinwardly extending fingers to form ball-retaining seats on said fingerswhereby said fingers have generally concentric concave facing surfaces,and cutting each of said radially outwardly extending portions with saidtool substantially concentrically with the axis of each respective holeto form two separate arcuate surfaces generally opposite one another ateach hole which have line contact portions thereon spaced from oneanother at a distance slight ly less than the diameter of said balls,whereby said two arcuate surfaces cooperate with one another to provideline contact with the ball associated therewith to hold the same fromfalling radially outwardly out of its pocket. 2. A method for making anannular ball retainer ring comprising the steps of forming a ring with aplurality of spaced radial holes with a single inwardly extending fingerand a single outwardly extending lug formed between adjacent holes, theholes having a diameter smaller than the diameter of the balls to bereceived therein, enlarging each of said holes with a cam-actuatedrecessing tool to a diameter larger than that of said balls and inwardlya predetermined distance short of the radially inner limit of saidinwardly extending fingers to form ball-retaining seats on said fingerswhereby said fingers have generally concentric concave facing surfaces,and cutting each of said outwardly extending lugs with said toolsubstantially concentrically with the axis of each respective hole toform two separate arcuate surfaces generally opposite one another ateach hole which have line contact portions thereon spaced from oneanother at a distance slightly less than the diameter of said balls,whereby said two arcuate surfaces cooperate with one another to provideline contact with the ball associated therewith to hold the same fromfalling radially outwardly out of its pocket. 3. A method for making anannular ball retainer ring comprising the steps of forming a ring with aplurality of spaced radial holes smaller than the balls to be receivedtherein, with an inwardly extending finger between adjacent holes andwith annular flanges spaced from one another by a distance slightly lessthan the diameter of said balls, said flanges extending radiallyoutwardly beyond the body of said ring, enlarging each of said holeswith a cam-actuated recessing tool to a diameter larger than that ofsaid balls and inwardly a predetermined distance short of the radiallyinner limit of said fingers to form ballretaining seats thereon, wherebysaid fingers have generally concentric concave facing surfaces, andforming with said tool arcuate line contact portions on the outerregions of said flanges which are substantially concentric with the axisof each respective hole, generally opposite one another at each hole,and spaced from one another at a distance slightly less than thediameter of said balls, whereby said portions cooperate with one anotherto form line contact with the ball associated therewith to hold the samefrom falling radially outwardly out of its pocket.

4. A method for making an annular ball retainer ring comprising thesteps of forming a ring having a main body portion,

providing spaced inwardly extending fingers on said forming portions onsaid ring which extend radially outwardly of the main body portion ofsaid ring,

and forming ball-receiving holes between said spaced fingers with acam-actuated recessing tool by moving the same inwardly a predeterminedpoint short of the radially inner limit of said inwardly extendingfingers to form ball-retaining seats thereon, whereby said fingers havegenerally concentric concave facing surfaces,

and cutting said radially outwardly extending portions with said toolsubstantially concentrically with the axis of each respective hole toform two separate arcuate surfaces generally opposite one another ateach hole which have line contact portions thereon spaced from oneanother at a distance slightly less than the diameter of said balls,whereby said two arcuate surfaces cooperate with one another to provideline contact with the ball associated therewith to hold the same fromfalling radially outwardly out of its pocket.

5. A method for making an annular ball-retainer ring,

comprising the steps of:

forming a ring with a plurality of spaced radial holes smaller than theballs to be received therein, with an inwardly extending projection andan outwardly extending projection adjacent each hole and of limitedarcuate extent about the hole axes at the location of adjacency to eachend of each hole,

and enlarging each of the holes to a radially extending whereby ballswhich slightly interfere with such seats at hole ends may be thereafterassembled into loosely retained unit-handling relation with said ring bysnap-action involving transient resilient local deflection at the seats.

References Cited UNITED STATES PATENTS 2,657,106 10/1953 Lovell et al s-3082l7 2,765,518 10/1956 Lovell et a1 29558 X 2,911,268 11/1959 Staunt308-201 2,933,803 4/ 1960 Schaeffler.

THOMAS H. EAGER, Primary Examiner US. Cl. X.R.

